curl and libcurl before 7.50.1 do not check the client certificate when choosing the TLS connection to reuse, which might allow remote attac
curl and libcurl before 7.50.1 do not check the client certificate when choosing the TLS connection to reuse, which might allow remote attackers to hijack the authentication of the connection by leveraging a previously created connection with a different client certificate.
- Published
- Aug 10, 2016
- Updated
- Jun 16, 2026
- EPSS
- 15.4% · 97th percentile
- CWE
- CWE-285
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Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 5 / 30 · 15.4%
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| haxx | libcurl | cpe:2.3:a:haxx:libcurl |
| opensuse | leap | cpe:2.3:o:opensuse:leap |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux8.0
- haxx libcurlup to 7.50.0 inclusive
- opensuse leap42.1
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | curl | before 7.50.1-r0 | 7.50.1-r0 |
| Alpine:v3.11 | curl | before 7.50.1 | 7.50.1 |
| Alpine:v3.2 | curl | before 7.49.1-r1 | 7.49.1-r1 |
| Debian:12 | curl | before 7.50.1-1 | 7.50.1-1 |
| Debian:7 | curl | before 7.26.0-1+wheezy14 | 7.26.0-1+wheezy14 |
| Debian:8 | curl | before 7.38.0-4+deb8u4 | 7.38.0-4+deb8u4 |
| Red Hat:enterprise_linux:7::client | curl | before 0:7.29.0-35.el7 | 0:7.29.0-35.el7 |
| Red Hat:enterprise_linux:7::client | curl-debuginfo | before 0:7.29.0-35.el7 | 0:7.29.0-35.el7 |
| Red Hat:enterprise_linux:7::client | libcurl | before 0:7.29.0-35.el7 | 0:7.29.0-35.el7 |
| Red Hat:enterprise_linux:7::client | libcurl-devel | before 0:7.29.0-35.el7 | 0:7.29.0-35.el7 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-curl | before 0:7.61.1-1.el6 | 0:7.61.1-1.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-curl-debuginfo | before 0:7.61.1-1.el6 | 0:7.61.1-1.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-httpd | before 0:2.4.34-7.el6 | 0:2.4.34-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-httpd-debuginfo | before 0:2.4.34-7.el6 | 0:2.4.34-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-httpd-devel | before 0:2.4.34-7.el6 | 0:2.4.34-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-httpd-manual | before 0:2.4.34-7.el6 | 0:2.4.34-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-httpd-tools | before 0:2.4.34-7.el6 | 0:2.4.34-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-libcurl | before 0:7.61.1-1.el6 | 0:7.61.1-1.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-libcurl-devel | before 0:7.61.1-1.el6 | 0:7.61.1-1.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-libnghttp2 | before 0:1.7.1-7.el6 | 0:1.7.1-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-libnghttp2-devel | before 0:1.7.1-7.el6 | 0:1.7.1-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-mod_ldap | before 0:2.4.34-7.el6 | 0:2.4.34-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-mod_proxy_html | before 1:2.4.34-7.el6 | 1:2.4.34-7.el6 |
| Red Hat:rhel_software_collections:3::el6 | httpd24-mod_session | before 0:2.4.34-7.el6 | 0:2.4.34-7.el6 |
+26
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Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:curl | 7.50.1-r0 · Alpine:v3.10 | Package registry (OSV) |
| debian:curl | 7.50.1-1 · Debian:12 | Package registry (OSV) |
| red hat:curl | 0:7.29.0-35.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:curl-debuginfo | 0:7.29.0-35.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:httpd24-curl | 0:7.61.1-1.el6 · Red Hat:rhel_software_collections:3::el6 | Package registry (OSV) |
| red hat:httpd24-curl-debuginfo | 0:7.61.1-1.el6 · Red Hat:rhel_software_collections:3::el6 | Package registry (OSV) |
| red hat:httpd24-httpd | 0:2.4.34-7.el6 · Red Hat:rhel_software_collections:3::el6 | Package registry (OSV) |
| red hat:httpd24-httpd-debuginfo | 0:2.4.34-7.el6 · Red Hat:rhel_software_collections:3::el6 | Package registry (OSV) |
| red hat:httpd24-httpd-devel | 0:2.4.34-7.el6 · Red Hat:rhel_software_collections:3::el6 | Package registry (OSV) |
| red hat:httpd24-httpd-manual | 0:2.4.34-7.el6 · Red Hat:rhel_software_collections:3::el6 | Package registry (OSV) |
| red hat:httpd24-httpd-tools | 0:2.4.34-7.el6 · Red Hat:rhel_software_collections:3::el6 | Package registry (OSV) |
| red hat:httpd24-libcurl | 0:7.61.1-1.el6 · Red Hat:rhel_software_collections:3::el6 | Package registry (OSV) |
| red hat:libcurl | 0:7.29.0-35.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libcurl-devel | 0:7.29.0-35.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| suse:curl | 7.19.7-1.20.42.1 · SUSE:Studio Onsite 1.3 | Package registry (OSV) |
| suse:curl-openssl1 | 7.19.7-1.61.1 · SUSE:Linux Enterprise Server 11-SECURITY | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-285 · Improper AuthorizationCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Accessing Functionality Not Properly Constrained by ACLsCAPEC-1likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Directory IndexingCAPEC-127likelihood: High · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
- Using Malicious FilesCAPEC-17likelihood: High · Very High
- Manipulating Opaque Client-based Data TokensCAPEC-39likelihood: High · Medium
- Bypassing ATA Password SecurityCAPEC-402
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
ATT&CK techniques
- Data from Local SystemT1005
- Query RegistryT1012
- File and Directory DiscoveryT1083
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Unsecured Credentials: Credentials in RegistryT1552.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Data Manipulation: Transmitted Data ManipulationT1565.002
- Hijack Execution Flow: Executable Installer File Permissions WeaknessT1574.005
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
- Hijack Execution Flow: ServicesFile Permissions WeaknessT1574.010
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.opensuse.org/opensuse-updates/2016-09/msg00011.html
- lists.opensuse.org/opensuse-updates/2016-09/msg00094.html
- rhn.redhat.com/errata/RHSA-2016-2575.html
- rhn.redhat.com/errata/RHSA-2016-2957.html
- www.debian.org/security/2016/dsa-3638
- www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
- www.securityfocus.com/bid/92309
- www.securitytracker.com/id/1036537
- www.securitytracker.com/id/1036739
- www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.563059
- www.ubuntu.com/usn/USN-3048-1
- access.redhat.com/errata/RHSA-2018:3558
- curl.haxx.se/docs/adv_20160803B.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GLPXQQKURBQFM4XM6645VRPTOE2AWG33/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3GQH4V3XAQ5Z53AMQRDEC3C3UHTW7QR/
- security.gentoo.org/glsa/201701-47
- source.android.com/security/bulletin/2016-12-01.html
- www.tenable.com/security/tns-2016-18
Vendor advisories and official records. Exploit/PoC links are deliberately left out.